Novel halo and amido substituted phenyltriphosphonitriles and preparation thereof



3,260,685 Patented July 12, 1966 "ice NOVEL HALO AND AMIDO YLTRIPHOSPHONITRILES AND THEREOF Rip G. Rice and Bernard Grushkin, Silver Spring, Md., assignors to W. R. Grace & Co., New York, N.Y corporation of Connecticut No Drawing. Filed June 11, 1963, Ser. No. 286,955

27 Claims. Cl. 260-2) 5 SUBSTITUTED PHEN- PREPARATION a LX 1.

wherein X represents halogen and n represents the number of repeating units in the polymeric structure. These polymeric phosphonitrilic halide polymers are linear in nature and possess elastomeric properties. Hence the term inorganic rubber is often used to describe them.

While the above described phosphonitrilic halides possess reasonable stability towards heat (350 C.), it is found they readily undergo hydrolysis, and hence find few practical applications.

To avoid the inherent shortcomings of the linear phosphonitrilic halides, highly crosslinked polymers of trimeric phenylphosphoni'trile amides were subsequently developed which do not contain reactive halo substituents. These highly cro-sslinked polymers are formed by heating trimeric phenylphosphonitrile amide to a temperature in excess of about 270 C. Polymer formation occurs with the formation of the following repeating unit It is seen that the above repeating structural unit bears three linkage valences and results in a highly crosslinked lattice type structure. While this lattice type structure ossesses many desirable characteristics where rigidity and high strength are required, it is found that the above phosphonitrilic polymers are too highly crosslinked to be readily soluble in most solvents. Furthermore, the highly crosslinked materials do not possess the flexibility required for many It 18 generally conceded that a predominantly linear phosphonitrilic polymer which possesses chemic inertness would be a useful addition to the family of inorganic polymers.

It is therefore an object of the present invention to provide a novel class i f phosphon'itrilic polymers.

It is another object to provide novel monogenated phenyl triphosphonitriles.

and dihalo- It is a further object to provide novel monoand dihalogenated phenyl triphosphonitriles from which predominantly linear phosphonitrilic polymers may be ultimately obtained.

It is still another object to provide linear phosphonitrilic I polymers which possess a high degree of thermal stability and chemical inertness.

It is yet a further object to provide a class of phosphonitrilic polymers which possess solubility in solvents and which may be used as surface coating compositions capable of being crosslinked to any desired degree.

These and still further objects of the present invention will become readily apparent to one skilled in the art from the detailed description and specific examples.

Broadly, the present invention contemplates novel h (phenylphosphonitriles) of the following formulae:

The invention also contemplates polymerizable ammoniated derivaties of the above phosphonitriles and polymers derived therefrom.

in the above formulae and occasionally hereafter, the

planar trimeric phosphonitrilic ring is represented from a side elevation as a straight line so that the sterero-isomerism of the phenyl (p) halo (X=Cl or Br), and other substituents may more easily be illustrated.

Compound I as illustrated above is named cis-2,4- dihalo-2,4,6,6-tetraphenyltriphosphonitrile, Compound II is trans-2,4 dihalo-2,4,6,6-tetraphenyltriphosphonitrile, and Compound III is 2-halo-2,4,4,6,6-pentaphenyltriphosphonitrile.

Compounds 1, H, and Ill may be converted to the corresponding amido derivatives by ammoniation to obtain the corresponding novel compounds set forth below Compound 1V illustrated above is 'cis-ZA-diamido- 2,4,6,6 tetraphenyltriphosphonitrile, V is trans-2,4- diamido-2,4,6,6-tetraphenyltriphosphonitrile, and V1 is 2 amido-2,4,4,6,6-pentaphenyltriphosphonitrile. a

Compounds IV and V may be individually or in combination heated under temperatures of from aboutr250 to 350 C. to obtain linear polymers which may be de- 4 scribed as cyclic trimeric phenylated pho-sphonitrilic rings action forms complexes with each Cl- P=N group preslinked together by amido bonds. These polymers may cut in the initial starting material. Hence, it is required graphically be shown as polymers possessing the repeatto add an excess of the aluminum halide in order to carry ing structural unit shown below out the reaction. This excess would be an amount greater than the molar amount of CI-P=N units which are present in the initial material These complexes which are ormed m the reaction are decomposed 1n the presence N e of dilute mineral acids. Therefore, when the phenylatton L {1; reaction is complete, the reaction mixture is admixed with L a dilute mineral acid, such as hydrochloric and sulfuric N n acid.

(VII) Subsequent to decomposition of the complexes the mixwh rei n represents h number of ,repeating units and ture is extracted with an organic solvent such as benzene represents phenyl. Furthermore compounds IV and to remove the phenylated triphosphonitriles. Solvents may be condensed in the presence of certain amounts 2 capped or terminated b nta h yltri h ho jt fle and carbon tetrachloride. The organic extract solution units. Such a terminated polymeric structure is illusy thbh be dried and the Solvents are evaporated whbfeby Hated b l a product residue is obtained which may be crystallized. 4) 29 Recrystallization may take place from any of the above organic solvents to give the desired phenyltriphospho nitrilic halide in the desired purity. s N N N N N N 5 The benzene used in the present reaction is the com L I I, l L l pound from Which the phenyl substituent is derived. It L J s is therefore found quite convenient to use benzene as the N N 11 N solvent for the reaction as Well as a reactant However (VIII) 1f desn ed ot er solvents may be used in COI'IJLIIICIIOII Wi h In the above formula represents ph nyl and n represents ehlehb Prbylded y are llfireactlve i h either the e number of repeating divalent functional units The e compounds or t e Teachoh Products Typlcal number n and hence the molecula weight of the above eXamples of solvents Which may be Used along With b511- structure may be regulated by adding controlled amounts zene are nitro-benzene and carbon disulfide In view of 0 monoamldopentaphenyl substltuted set fo th as com the fact that these solvents result 1n the dilu ion of the pound VI above which acts as a cham stoppmg aoent SIOHCCHlIIitlOH of bgnzene 1n the reaction mixture which D in turn ecreases t e rate of reaction It is preferred that PREPA A OF l q l gllgg H0 the amount of these solvents be hept to a minimum.

We have found that good yields of compounds I, II and to about 100 parts of benzene is employed pe III set forth above may be made by reacting cisor transchlorotriphenyltriphosphonitrile starting material. Fur- 2,4,6 m'ha1 2,4,6 triphenyltriphosphonitrile having the thermore, a ratio of from 40 to 60 parts of benzene per f l 40 part of trichlorotriphenyltriphosphonitrile will provide X X particularly satisfactory results.

[ {LL s pointed out a ove, complexes are formed with he I a uminum halides used in t e reaction and an excess of X X X X a umtnum halide is required Generally, there is usua ly (IX) (X) at east 6 moles of aluminu halide present per each mole wherein 95 represents phenyl and X represents hromo or of tnchlorotriphenyltriphosphomtrile starting material chloro, with benzene 1n the presence of aluminum trian as 1g as m0 es 0 a ummum hahde may be used chhmde or alummum Lnhroml e s a generally preferred range, from about 15 to 36 moles 11 may be carried out by adding anhydrous o alumihuln halide P mole b trlchlorotrlphehyltfialuminum chloride or bromide to a rapidly stirred solu- O llhosphommle found be Particularly e ct ve. If detion of 2,4,6 trihalo-2,4,6-triphenyltriphosphonitrile in the al'u'mmum hahde y be added t0 the r action benzene and then heating the mixture at reflux. Dry inert mlxturefln at of in P t ns during the reaction. gas such as nitrogen may be passed through the reaction heaqhon condltlons W 1.6 are Particularly lhdllclye 0 mixture to remove hydrogen halide WhICh IS evolved. ,mnatlon of h desired Phenylated mpounds involve The hydrogen halide obtained from the reaction may be 1131} P F 3gltah0n dunhg the TeaCtIOII Period This dissolved in water and titrated at intervals during the Tapld }Q serves to i perse the aluminum halidecourse of the reaction. These titrations will indicate the phosghqmmlw Complexes Which are present in an insolunumher of moles of halogen Whl-hh is replaced by phenyl ble o1l-l1ke state. Unless this oil is kept in a dispersed groups and hence the progress of the phehylah-oh may condition the rate of t e action is considerably dedetermined at anytime during the reactto 69 creasedt is found that the phenylatron reaction first substitutes Temperatures used to rry Out the present reaction one halo group to produce the compounds I and/or II set W111 Vary from about 50 to about C chnanly the forth above. e second halo group is more diflicult to reactlon temperatures at about the boiling point of the substitute and onger reflux times are generally requlred. Solvent used q y n are entirely satisfacen it is desired to produce tetra phenylated compounds tory for the Practlce for the Present Invention p (I and II), that 15 compounds Whlch bear two ha 0 groups, atures in excess of the reflux temperature of the solvent t e reaction is terminated when an amount of hydrogen used contemplated Provided l a le pressure equip- :hloride is liberated which corresponds stoichiometrically ment 15 usedto the substitution of only one halo group. P P

On the other hand, if it is desired to obtain the com- 7 g i gg round of the Formula III bearing only one halo group, he reaction is run f0 ra longer period until the amount The compounds 01's ,dlamido 2,4,6,6 tetrahydrogen halide evolved stoichiometrically represents phehyltrlbhosphohltflle, trans 2,4,dlhh1ld0 5- ie amount required for substitution of two halo groups. p ny ph ph nitrile, and 2 amido 2,4, ,6,6-

It is found that the aluminum halide used in the re pentaphenyltriphosphonitrile portrayed as compounds IV, V and VI above, which are used as intermediates in the preparation of the polymers set forth herein, are prepared by reacting the corresponding halo compounds I, II and III with ammonia. This is accomplished by either passing gaseous a solution of I, II or III (or mixtures thereof) in an inert solvent, or by adding a solution of the halo compound to liquid ammonia.

During the course of the reaction the halo substituents of the triph-osphonitrilic compounds are substituted by amido groups. Thus during the reaction ammonium chloride is produced in stoichiometric quantities. For each mole of halogen which is substituted one mole of ammonium chloride will be produced. This ammonium chloride is precipitated as the reaction proceeds. sequent to reaction, the precipitated ammonium halide may be titrated for chloride ion and hence serve .as a measure of the completeness of the reaction.

Solvents which may be used during the ammoniation of the halo triphosphonitrile are inert solvents such as chloroform, carbon disulfide, carbon tetrachloride, and benzene.

Temperatures used for the ammoniation when ammonia gas is passed through a solvent of the halo (phenyltriphosphonitrile) range from about to about 80 degrees C. When liquid ammonia is used temperatures in the range of from about -75 to about -35 C. are preferred. Using these temperatures substantial yields are obtained within /2 to 3 hours.

Subsequent to the ammoniation, the reaction mixture may be filtered to remove precipitated ammonium halide and the solvent may be removed by distillation. This will yield the desired amidotriphosphonitriles as a solid residue. The precipitated product may then be recrystallized from inert solvents such as chloroform-pentane, benzene-hexane, and cyclohexane to produce a product of the desired purity.

PREPARATION OF PHOSPHONITRILIC POLYMERS The polymers of our present invention, which are de-' fined as repeating amido (tetraphenyltriphosphonitrilic) units terminated by pentaphenyltriphosphonitrile units as set forth in Formula VIII above, are prepared by heating the amido derivatives IV, V and VI at temperatures of from about 250 to about 350 C., preferably under reduced pressure or under an inert atmosphere, such as helium or nitrogen.

During the heating step, the amido derivatives IV, V and VI condense through the amido groups with evolution of ammonia. It is seen that compounds IV and V bearing two amido groups will polymerize in a linear fashion. This polymerization will occur until terminated by the compound of Formula VI which bears a single amido group.

Using the temperatures in the range of 250 to 350 C. substantial polymerization is obtained in from about'10 to about 30 minutes. It is generally preferred that the polymerization be conducted under a vacuum to hasten the reaction mixture; although inert atmospheres at atmospheric pressure may be used. Pressures as low as 10 millimeters of mercury have been employed and even lower pressures would produce a desirable result.

The ammonia which is evolved from the polymerization may be collected in a suitable trap. Its volume may be measured and therefore the progress of the polymerization may be closely scrutinized.

The polymers obtained from the polymerization are sol ble in a variety of organic solvents such as benzene, chloroform, acetonitrile, dioxane, ethyl acetate, acetone and dimethyl formamide. The polymers may possess a molecular weight of from about 2000 to about 4000.

These inorganic polymers which do not possess carbon to carbon bonds in the backbone chain are extremely These polymers are useful in the 1000 C.

stable towards heat. range of from about 300 to about I The above linear polymers may be effectively crosslinked by using a small amount of 2,4,6-triamido-2,4,6- triphenyltriphosphonitrile as a crosslinking agent. The 2,4,6 triamido 2,4,6 triphenyltriphosphonitrile may be obtained by reacting phenyltetrachlorophosphorane, and ammonium chloride. This results in a 2,4,6-trichloro-2,4,6-triphenyltriphosphonitrile which may be ammoniated in a manner simi ax to that described in the preparing of compounds IV, V and VI of the present invention. Incorporation of these triamidotriphenyltriphosphonitriles results in the formation of crosslinks which are illustrated in the unit formula set forth below -NH-P NH-P P- L N n N L N in (In the above formula the phenyl groups attached to the phosphorus atoms have been omitted for clarity.)

In practice, the crosslinking of the present linear polymers is obtained by adding from about 1 to about 25% of 2,4,6 triamido 2,4,6 triphenyltriphosphonitrile by weight of the linear polymer.

In a typical coating composition from about 10 to about 50% by weight of the above polymer (XI) may be combined with a solvent such as chloroform, dirnethylfonmamide, or other non-reactive solvent. Such a coating solution is applied to a substrate, the solvent is evaporated, and final curing of the polymers takes place at the condensation temperature of about 250 to 350 C. Such coating is tough, impact resistant, and insoluble in most common organic solvents. Furthermore, the coating is rSesist-ant to hydrolysis and temperatures up to about Having described the basic aspects vention the following specific examples trate embodiments thereof.

of the present inare given to il us- Example I To a solution of 10.0 g. of trans-2,4,6-trichloroe2,4,6- triphenyltriphosphonitrile in 200 ml. of benzene (dried over calcium hydride), was added 60 g. of anhydrous aluminum chloride and an additional ml. of anhydrous benzene. The mixture was agitated vigorously and heated at reflux. Dry nitrogen gas was passed through the mixture, then into a stirred water tra containing bromthymol blue indicator. The absorbed hydrogen chloride then was titrated with 0.1 N sodium hydroxide at in-' tervals.

After 1 hour of refluxing, the reaction was about 30%,.

complete for substitution of one phenyl group. An additional 15 g. of anhydrous aluminum chloride was added and stirring and refluxing were continued. After a total of 1.75 hours the reaction was nearly 60% completed. An additional 15 .g. portion. of aluminum chloride was added, and, after a total of 2.75 hours, thereaction was 95% completed. A further 10 num chloride was added, and the mixture was stirred an refluxed an additional 20 minutes (total time of reflux, about 3 hours). By HCl measurement the reaction was completed for substitution of one phenyl group, i.e., one chloride atom had been completely substituted, a second had been partially (15%) substituted.

The reaction a mixture of ice,

water and 10% hydrochloric acid to deg. of anhydrous alumi-.

clohexane. A first crop Weighing 3.82 g. Was obtained, M. 18 -92 C., of cis-2,4-dichloro-2,4,6,6-tetraphenylanalytical sample melted at triphosphonitrile. 1956 C.

Calculated for C24H20N3P C'l2: N:8.17; Cl:t13.79; wt. 514. Found: C:55.78; H:3.25; N:8.66; Cl:l4.33; mol wt. 51

cyclohexane filtrate gave 3.65 g. of a second crop, M. 164 C. of trans-2,4,6,6-tetraphenyltriphosphonitrile. An analytical sample melted at 169 70 C.

Calculated for C H 'N 'P Cl (3:56.05; H:3.92; N:8.17; 01:13.79; mol. wt. 514. Found C:55.92; H=3.93; N:8.0 6; 01:13.27; mol wt. 529.

Dilution of this second filtrate with pentane produced 2.04 g. of a third crop which melted from 150 to 175 Fractional recrystallization gave 0.38 g. of cis-tetraphenyldichloro compound, M. 185-9 C., and 1.02 g. of a solid solution of the cisand trans-dichloro isomers Which melted at 1529 C.

The infrared spectra of the cisand trans-isomers, as Elemental agreed with that of a Example II In a manner analogous to that of Example I, 10.0 g. of cis-2,4,6-trichloro 2,4,6 triphenyltriphosphonitrile was treated with anhydrous aluminum chloride. After 1.1

Example Ill pentaphenyltriphosphonitrile,

le melted at l512 C.

Calculated for C H N P Cl. C:64.81, H:4.53, :7 57; Cl:6 38%; mol. wt. 556. Found: C=65.36;

68' N:7.45; Cl:6.47%; mol. wt. 524.

Example IV In a manner analogous to that of Example II, 5.00 g. of cis-2,4,'6-trichloro-2,4,6,-triphenyltriphosphonitrile gave 4.00 g. of 2-chloro-2,4,4,6,6-pentaphenyltriphosphonitrile, M. 14951 C.

Example V 80-90 C. through- Substantially the same :sults are obtained as in Example I, except that heating times nearly double those of Examples I and II quired.

were 1%- Example VI The procedure of Example II is followed except employing anhydrous aluminum bromide, in place of the aluminum chloride. Substantially the same yield of cisand trans-2,4-dichloro-2,4,6,6-tetraphenyltriphosphonitrile is obtained.

Example VII Anhydrous gaseous ammonia was passed slowly through 75 ml. of rapidly stirred chlorofor To this was added a solution of 1.50 g. of cis-2,4-dich1oro-2,4,6,6-tetraphen- C24H24P3N5 N: 14.73; mol wt. 4754. Found: C:60.56, 60.68; H:5.25, 5.86; N:14.53, 14.64; mol. wt. 492 (in acetonitrile).

Example VIII In an analogous manner to that described in Example II, 1.50

g. of trans-2,4-dichloro-2,4,6,6-tetraphenyltfhours at l0-39 C.

monium chloride (theoretical:0.313 g) of the filtrate gave 1.47 g. of solid, which, recrystallized frome benzene-pentane, melted at 149-50 C.

Calculated for C H P N C:60.63; H:5.09; N: mol. wt.:475.4. Found: C:60.89; H:5.13; N=14.40; mol. wt.:497 (in acetonitrile).

Example IX In a manner analogous to that of Example VIII, 1.50 g. of a solid solution of cisand trans-isomers of 2,4-dichime-2,4,6,6-tetraphenyltriphosphonitrile,

' of cisand trans-isomers of 2,4-diam1do-2,4,6,6-tetraphenyltri- Example X Example XI In a high vacuum apparatus 0.5 g. of cis-2,4-diamido- 2,4,6,6-tetraphenyltriphosphonitrile was heated slowly by means of an oil bath to 345-365 C. in 1 hour then heated 3 hours at 345365 C. i

0 to 10 millimeters of mercury and benzene, chloro- Its in- Example XII In a manner analogous to that of Example XI, 0.50 g. of trans 2,4-diamido-2,4,6,6-tetraphenyltriphosphonitrile was polymerized 2.5 hours at 343-360 C. and at pressures of 10- to 10" millimeters of mercury. the end of this time there had been evolved 1.04 mole of ammonia per mole of diamidophosphonitrile. The residual polymer had exactly the same solubility characteristics as did that from the cis-diamido compound. Its infrared spectrum also showed strong triphosphonitrilic ring absorption at 1210 cmf Its molecular weight, determined by vapor pressure osmometry in benzene, was 2490.

Example XIII In a manner analogous to that of Example XI, 0.50 g. of the mixture of cisand trans-2,4 diamido-2,4,6,6-tetraphenyltriphosphonitrile, prepared as in Example IX was heated under reduced pressure to produce a polymer having properties similar to those of the polymers prepared in Examples XI and XII.

l Example XIV A solution was prepared from 1.00 g. of the polymer from trans 2,4-diamido-2,4,6,6-tetraphenyltriphosphonitrile. (prepared as in Example XII), 0.10 g. of trans-2,4,6- triamido-Z,4,6-triphenyltriphosphonitrile, and 3.7 g. of N,N-dimethylformamide. This solution was brushed onto anodized alumin and titanium strips. The coated strips were air dried overnight, then hours at 145-150, then 2 hours at 200, and finally 2 hours at 300-325".

The coatings are highly adherent to the metal substrates, are tough and resistant to impact, and are insoluble in common organic solvents such as chloroform, benzene, acetone, etc. In addition, the coatings are not afiected by immersion in boiling water. I

We claim:

1. Compounds selected from the group consisting of -cis-2,4-dichloro-2,4,6,6 tetraphenyltriphosphonitrile and trans-2,4-dichloro-2,4,6,6-tetraphenyltriphosphonitrile.

2. The compound cis 2,4-dichloro-2,4,6,6-tetraphenyltriphosphonitrile.

3. The compound trans triphosphonitrile.

4. A method for preparing compounds of the formula 2,4-dichloro-2,4,6,6-tetraphenylselected from the group consisting of bromine and chlorine, and R is selected from the group consisting of phenyl, bromine and chlorine which comprises forming a reaction mixture of 2,4,6- trihalo-2,4,6-triphenyltriphosphonitrile with benzene and an aluminum halide of the formula AIXg, wherein X is selected from the group consisting of chlorine and bromine, said AlX being present in amounts greater than 3 moles of AlX per mole of 2,4,6-trihalo-2,4,6-triphenyltriphosphonitrile, heating said reaction mixture to a temperature of from about 50 to about 90 C. until hydrogen halide is evolved, and recovering the above triphosphonid from the reaction mixture.

5. wherein said AlX compound is present in ranging from about 6 to about 50 moles of trihalotriphenyltriphosphonitrile present.

6. The method of claim 5 wherein from about 10 to about 100 parts by weight benzene is present per part of trihalotriphenyltriphosphonitrile present.

7. The method of claim 4 carried out of an inert solvent.

8. The method of claim 4 wherein subsequent to heating in the presence said reaction mixture is contacted with a mixture of water and mineral acid to decompose aluminum halide complexes which are present, and the desired phosphonitrilic halide is extracted with a water immiscible inert solvent.

9. Compounds selected from the group consisting of cis 2,4 diamido 2,4,6 tetraphenyltriphosphonitrile and trans-2,4-diamido-2,4,6,6-tetraphenyltriphosphonitrile.

10. The compound cis 2,4-diamido-2,4,6,6-tetraphenyltriphosphonitrile.

11. The compound trans phenyltriphosphonitrile.

12. A phosphonitrilic polymer possessing the repeating structural unit 2,4 diamido 2,4,6,6 tetra- P N N H l -NH-P P- L p N e wherein :1: represents phenyl. 13. A phosphonitrilic polymer possessing the structure 4 P P P N N N N N N I it l l/ P P NE P P NH- P N 4* 4 N 4 l1 4* N wherein represents phenyl, and n is an integer of from about 1 to about 10.

14. A crosslinked phosphonitrilic polymer which contains the structural unit wherein represents phenyl which comprises heating a compound of the formula discontinued when ammonia ceases to evolve.

a temperature of from 19. A method for preparing a phosphonitrilic polymer of substantially linear the structure h comprises heating a mixture 'ng 2,4 diamido-2,4,6,6-tetraphenyltriphosphonitrile, and 2-amid-o-2,4,4,6,6-pentapheny1triphosphonitrile, said 2-amido-2,4,4,6,6-pentaphenyltriphosphonitrile being present in amounts of from about 0.01 to about 2.0 moles per mole of said 2,4-diamid-2,4,6,6-pentaphenyltriphosphonitrile, to a temperature of from about 250 to 350 C., continuing said heating until ammonia substantially ceases to evolve.

20. The method of claim 15 Which comprises heating 2,4-diamido-2,4,6,6-tetraphenyl triphosphonitrile in the presence of from about 0.01 to 0 mole of 2,4,6-triamido-2,4,G-triphenyltriphosphonitrile per mole of 2,4-diamido-2,4,6,6-tetraphenyltriphosphonitrile to a temperature of from about 250 to per parts by Weight of 2,4,6-triamido-2,4,6-triphenyltriphosphonitrile dissolved in a volatile inert solvent.

he composition of claim 25 wherein the vent possesses a boiling point of from about 200 C.

inert solto about References Cited by the Examiner SAMUEL H. BLECH, Primary Examiner.

1960, pp. 126436. Chemistry and Industry, January 26,

and Industry, September 17, 

12. A PHOSPHONITRILIC POLYMER POSSESSING THE REPEATING STRUCTURAL UNIT 